Labour leader David Cunliffe has urged Christchurch East voters to "get out of bed'' and vote in tomorrow's by-election as the contest nears the finish line.

He was hardly oozing confidence on the eve of the by-election that most pundits say should be won by Labour's Poto Williams tomorrow night.

Cunliffe, with Williams at his side, was talking up her credentials for the job, but admitted the party was starting 4500 party votes behind on National.

At the 2011 election, National embarrassed Labour by comfortably winning the party vote. Tomorrow's by-election is purely a vote for the candidate.

Cunliffe said Labour had been working very hard to make up that party vote loss in 2011 but it was "essential'' people had to get out and vote to secure the seat which has been held by Labour since it was formed in 1922.

When asked if he was confident about retaining the seat, Cunliffe said he never used the word "confident.''"I run every race like you're going to lose by one vote.''

He declined to comment on whether a loss would be a damaging body-blow to his relatively new leadership of the party, saying "let's just see how tomorrow rolls.''

He also rubbished claims Williams was not local enough for the electorate. She moved from Auckland at the start of the year after a career in social and community service.

Cunliffe said she was the only candidate he knew of that lived in the electorate and moved into the area after the earthquakes when so many people left.

"Her career history is one of service to the community so ... our (Auckland's) loss is Christchurch's gain.''

"If people want a Labour MP who will work hard, they are going to have to get out of bed and vote for (Williams). We are taking nothing for granted.''

This afternoon, Cunliffe and Williams will campaign in the Palms shopping mall before both speak at a series of street corner meetings later in the day.

Cunliffe will stay in Christchurch until Sunday morning and will be attending the Labour election night function where both he and Williams are expected to address their supporters once the final result is known.

The Electoral Commission said it was working towards releasing voting result updates during the night.

The first is expected around 9pm when half the votes have been processed while the final result is expected to come about 10pm but these times could change.